<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>promise</title>
    <script>
        let arr = new Array();

        let set = new Set();

        set.add("heima60");
        set.add("heima60");
        set.add("heima60");

        let user = {
            name:"ldh",
            friend:{
                name:"zxy",
                age:50
            }
        }

        console.log(set.size);

        console.log(user)



    </script>
</head>
<body>

</body>
</html>